Fiber lasers emitting in the 2 μm wavelength range doped with thulium ions can be used as highly efficient pump
sources for nonlinear converters to generate mid-infrared radiation. For spectroscopic purposes, illumination and
countermeasures, a broad mid-infrared emission spectrum is advantageous. This can be reached by supercontinuum
generation in fibers, e.g. fluoride fibers, which up to now has, however, only been presented with either low
average power, complex Raman-shifted 1.55 μm pump sources or multi-stage amplifier pump schemes. Here we
present recent results of a new actively-mode-locked single-oscillator scheme that can provide the high-repetition
rate sub-ns pump pulses needed for pumping supercontinuum generators. A thulium-doped silica fiber laser is
presented that provides > 11 W of average power CW-mode-locked pulses at 38 MHz repetition rate at ~ 38 ps
pulse width. Upgrading the setup to allow Q-switched mode-locked operation yields mode-locked 40 MHz pulses
arranged in 60 kHz bunched Q-switch envelopes and thus increases further the available peak power. In this
Q-switched mode-locked regime over 5 W of average power has been achieved.